1. Technical Field
The invention relates to a printing apparatus and a printing method that allows the number of printing passes, the printing pass ejecting a liquid from a printing head while the printing head is displaced in a main scanning direction, to be set from a plurality of numbers, and, in particular, the present invention relates to a printing apparatus and a printing method to which a printing technique employing a photocurable liquid is applied.
2. Related Art
Hitherto, an apparatus has been known that carries out an operation called a printing pass, the printing pass being an operation in which a print head is displaced in a main scanning direction while a liquid such as ink is ejected onto the printing medium from the print head, for a plurality of times in order to carry out printing on a predetermined width of a printing medium in a sub-scanning direction. Furthermore, as described in JP-A-2004-188891 and JP-A-2009-202418, a printing technique employing a photocurable liquid can be applied to the apparatus. Specifically, in JP-A-2004-188891 and JP-A-2009-202418, light irradiators that move with the print head are provided. Moreover, the light irradiators follow the print head, which moves in the main scanning direction to carry out a printing pass, and irradiate light at the same time; accordingly, light is radiated on the liquid that has been ejected onto the printing medium by the print head and the liquid is cured. In particular, in JP-A-2009-202418, two types of light irradiators (a light irradiator for a preliminary cure and a light irradiator for a full cure) with different irradiation intensities are provided. Moreover, as the printing pass is carried out, a weak light is radiated from the light irradiator for a preliminary cure that follows the print head to promptly perform preliminary curing of the liquid ejected during the printing pass. Furthermore, the light irradiator for a full cure irradiates a strong light on the area of the printing medium where a predetermined number of printing passes have been completed; accordingly, the liquid is fully cured.
The configuration described above, which carries out photoirradiation on the liquid in two stages, namely, the preliminarily curing stage and the fully curing stage, is conceived to have an advantage in stabilizing the image quality. However, as described in JP-A-2004-188891 and JP-A-2009-202418, in apparatuses that carry out printing by executing plural numbers of printing passes, if control of the photoirradiation that is carried out in steps is inadequate, there are cases in which stabilization of the image quality is not efficiently achieved ultimately. In other words, in apparatuses that are provided with a light irradiator that follows the print head as the printing pass is carried out, the integrated quantity of light that will be radiated may increase each time the printing pass is repeated. Accordingly, as pointed out in JP-A-2009-202418, in some cases, the image quality changes depending on the number of printing passes that is carried out for printing and, thus, there are cases in which the image quality is unstable. Accordingly, appropriate control of photoirradiation that is in accordance with the number of printing passes is needed. However, JP-A-2004-188891 and JP-A-2009-202418 do not describe on how to control the photoirradiation, which is carried out in steps, in accordance with the different numbers of printing passes.